1. Field of the Invention
The present invention relates to a substrate processing apparatus for overlaying and contacting two substrates with each other, a substrate support apparatus, and a substrate processing method, and a substrate manufacturing method using the apparatus or method.
The present invention also relates to a substrate support table consisting of a silicon material, a substrate processing apparatus including the substrate support table, methods of manufacturing and handling the substrate support table, and a substrate processing method.
2. Description of the Related Art
There is a method of bringing two wafers (substrates) into contact and bonding them by anode bonding, pressing, or heat treatment. This method is suitable to manufacture a wafer having, e.g., an SOI structure.
FIGS. 14A and 14B are schematic views showing the step of bonding wafers. In this bonding step, first, a first wafer 1 with its bonding surface facing up is set on a wafer support jig 201, and a second wafer 2 with its bonding surface facing down is softly placed on the first wafer 1, as shown in FIG. 14A. At this time, the upper wafer 2 floats on the gas (e.g., air or an inert gas) between the wafers, as shown in FIG. 14A.
As shown in FIG. 14B, when a press pin 202 presses the upper wafer 2 near its central portion before the gas between the wafers 1 and 2 is completely removed, the air at the central portion of the wafers moves to the periphery. The wafers 1 and 2 come into contact with each other at the central portion first. As the gas between the wafers gradually moves outward, the contact area expands, and finally, the entire wafers come into contact with each other.
Although the above method is applicable to bring two wafers into contact by simple operation, it has the following problems.
One of the problems is associated with wafer contamination due to alignment of two wafers. Since the upper wafer 2 floats on the gas between the wafers, friction in moving the upper wafer 2 in the horizontal plane is very small. The upper wafer 2 slides even when the jig 201 slightly tilts. Therefore, to properly align the two wafers 1 and 2, a means for limiting movement of the wafer 2 in the horizontal plane is required.
The jig 201 shown in FIGS. 14A and 14B has a recessed portion conforming to the shape of the wafers 1 and 2. The wafers 1 and 2 are aligned while being limited in their movement in the horizontal direction by the side walls of the recessed portion.
FIG. 15 is a view showing another jig for overlaying the wafers 1 and 2 while aligning them. A jig 205 has a plurality of alignment pins 204 and a press pin 203. The wafers 1 and 2 are pressed against the plurality of alignment pins 204 by the press pin 203, thereby limiting movement of the wafers 1 and 2 in the horizontal plane.
The method of overlaying two wafers using the jig shown in FIGS. 14A and 14B or FIG. 15 has factors that generate particles, inflict damage to the peripheral portions of the wafers, or lower the yield because the peripheral portions of the wafers are in contact with the jig.
As another problem, no constant condition can be obtained in pressing the wafers. More specifically, the time after the two wafers are overlaid until they are pressed by the press pin is not constant, and the gap between the wafers in pressing them by the press pin is not constant. Therefore, the quality of the wafer obtained by bringing two wafers into contact can be lowered by the resulting lack of uniformity. In addition, the gas between the wafers sometimes escapes before the wafers are pressed by the press pin. In this case, since the wafers cannot be brought into contact while gradually removing the gas outward from the central portion, some gas may remain entrapped between the wafers.
As an apparatus for supporting a substrate to be processed in the manufacture of a semiconductor device, a substrate support apparatus for supporting a substrate by vacuum chucking is used. As a substrate support table, i.e., a unit of the substrate support apparatus, normally, a plate consisting of a metal or ceramic material with high rigidity and having a chuck groove is used.
However, the conventional substrate support table is expensive in general, and a demand for a more inexpensive substrate support table has arisen.
The present invention has been made in consideration of the above problems, and has as its object to increase the quality of a substrate obtained by bringing two substrates into contact with each other.
According to the present invention, there is provided a substrate processing apparatus for overlaying two substrates and bringing the substrates into contact with each other, characterized by comprising support means for supporting the first substrate; and pressing means for pressing the second substrate against the first substrate, the second substrate opposing the first substrate supported by the support means, wherein the support means has a support member contacting a peripheral portion of one surface of the first substrate to support the first substrate.
In the substrate processing apparatus, the support means preferably has chuck means for chucking the first substrate on the support member.
In the substrate processing apparatus, preferably, the chuck means has an annular groove on a surface of the support member, and the first substrate is chucked by the support member by reducing a pressure in the groove.
In the substrate processing apparatus, the support member preferably has an annular shape.
In the substrate processing apparatus, the support member preferably supports an outermost portion of one surface of the first substrate.
In the substrate processing apparatus, the pressing means preferably presses the second substrate substantially at a central portion thereof.
In the substrate processing apparatus, the support means preferably has, inside the support member, a deflection prevention member for preventing deflection of the first substrate.
In the substrate processing apparatus, the deflection prevention member preferably supports the first substrate substantially at a central portion thereof, thereby preventing deflection of the first substrate.
In the substrate processing apparatus, a portion where the support member is in contact with the first substrate and a portion where the deflection prevention member is in contact with the first substrate are preferably positioned substantially in the same plane.
Preferably, the substrate processing apparatus further comprises substrate manipulation means for canceling support of the second substrate after the second substrate is supported to oppose the first substrate supported by the support means, and the pressing means presses the second substrate in synchronism with cancel of support of the second substrate by the substrate manipulation means.
In the substrate processing apparatus, preferably, the support means substantially horizontally supports the first substrate, and the substrate manipulation means substantially horizontally supports the second substrate above the first substrate and then cancels support of the second substrate.
According to the present invention, there is also provided a substrate support apparatus for supporting one of two substrates to be overlaid and brought into contact with each other, characterized by comprising a support member contacting a peripheral portion of one surface of a substrate to support the substrate.
The substrate support apparatus preferably further comprises chuck means for chucking the substrate on the support member.
In the substrate support apparatus, preferably, the chuck means has an annular groove on a surface of the support member, and the substrate is chucked by the support member by reducing a pressure in the groove.
In the substrate support apparatus, the support member preferably has an annular shape.
The substrate support apparatus preferably further comprises, inside the support member, a deflection prevention member for preventing deflection of the substrate.
In the substrate support apparatus, the deflection prevention member preferably supports the substrate substantially at a central portion thereof, thereby preventing deflection of the substrate.
In the substrate support apparatus, a portion where the support member is in contact with the substrate and a portion where the deflection prevention member is in contact with the substrate are preferably positioned substantially in the same plane.
According to the present invention, there is also provided a substrate processing method of overlaying two substrates and bringing the substrates into contact with each other, characterized by comprising supporting a first substrate by a support member contacting a peripheral portion of one surface of the first substrate, and pressing a second substrate toward the first substrate, the second substrate opposing the first substrate, thereby bringing the first and second substrates into contact with each other.
In the substrate processing method, preferably, a support member having a chuck mechanism is used as the support member.
In the substrate processing method, preferably, an annular support member is used as the support member.
In the substrate processing method, the support member preferably supports an outermost portion of the first substrate.
In the substrate processing method, the second substrate is preferably pressed substantially at a central portion thereof.
In the substrate processing method, the step of pressing the second substrate preferably comprises bringing a deflection prevention member formed inside the support member into contact with the first substrate.
The above apparatus and method are suitable to manufacture a SOI substrate.
According to the present invention, there is provided a substrate processing method of overlaying two substrates and bringing the substrates into contact with each other, characterized by comprising the steps of transferring first and second substrates to any one of the above substrate processing apparatuses, overlaying the first and second substrates and bringing the substrates into contact with each other by the substrate processing apparatus, and receiving the substrates in contact with each other from the substrate processing apparatus.
According to the present invention, there is also provided a substrate processing method of overlaying two substrates and bringing the substrates into contact with each other, characterized by comprising the steps of causing any one of the above substrate support apparatuses to support a first substrate, opposing a second substrate to the first substrate supported by the substrate support apparatus, and overlaying the first substrate and the second substrate and bringing the substrates into contact with each other.
According to the present invention, there is also provided a method of manufacturing a substrate, characterized by comprising the steps of preparing first and second substrates, and bringing the first and second substrates into contact with each other by any one of the above substrate processing methods.
According to the present invention, there is also provided a method of manufacturing an SOI substrate, characterized by comprising the steps of preparing first and second substrates, bringing the first and second substrates into contact with each other by any one of the above substrate processing methods to prepare a substrate having a layer in which a single-crystalline Si layer and an insulating layer are stacked, and separating the substrates which are in contact with each other at a portion other than a contact interface to prepare one of the separated substrates as the substrate having the single-crystalline Si layer on the insulating layer.
The present invention has been made in consideration of the above problems, and has as its object to provide an inexpensive substrate support table.
According to the present invention, there is provided a substrate support table characterized by comprising a member consisting of a silicon material.
According to the present invention, there is also provided a substrate support table characterized by comprising a member formed from a silicon wafer.
The substrate support table preferably comprises a chuck portion for chucking a substrate to be supported.
In the substrate support table, the chuck portion is preferably formed by lithography.
In the substrate support table, the chuck portion is preferably formed by etching the silicon wafer.
In the substrate support table, the chuck portion is preferably formed by wet-etching the silicon wafer.
In the substrate support table, the chuck portion preferably includes sealing portions for vacuum-chucking the substrate and a suction hole for exhausting a gas in a space defined by the sealing portions.
In the substrate support table, preferably, the sealing portions are doubled along inside a periphery of the substrate to be supported, and the suction hole communicates with the space between the doubled sealing portions.
In the substrate support table, the sealing portions preferably project to have a bank shape at the periphery.
In the substrate support table, preferably, in chucking the substrate, only the sealing portions are brought into contact with the substrate.
The substrate support table preferably further comprises a deflection prevention portion for preventing the chucked substrate from deflecting.
In the substrate support table, the deflection prevention portion is preferably formed between the sealing portions.
In the substrate support table, preferably, in chucking the substrate, only the sealing portions and the deflection prevention portion are brought into contact with the substrate.
In the substrate support table, the surfaces of the sealing portions and the deflection prevention portion, which are in contact with the substrate to be supported, are preferably positioned substantially in the same plane.
In the substrate support table, the chuck portion is preferably located at a position where a peripheral portion of the substrate to be supported can be chucked.
In the substrate support table, preferably, a pin hole through which a load pin for vertically moving the substrate to be supported on the substrate support table is inserted extends through the main body.
The silicon wafer preferably complies with the SEMI standard or the JAIDA standard.
According to the present invention, there is provided a substrate processing apparatus for overlaying two substrates and bringing the substrates into contact with each other, characterized by comprising an attachment/detachment mechanism for attaching/detaching the substrate support table, and pressing means for pressing a second substrate toward a first substrate supported by the attached substrate support table, the second substrate opposing the first substrate.
In the substrate processing apparatus, the pressing means preferably presses the second substrate substantially at a central portion thereof.
Preferably, the substrate processing apparatus further comprises substrate manipulation means for canceling support of the second substrate after the second substrate is supported to oppose the first substrate supported by the substrate support table, and the pressing means presses the second substrate in synchronism with cancel of support of the second substrate by the substrate manipulation means.
In the substrate processing apparatus, preferably, the substrate support table substantially horizontally supports the first substrate, and the substrate manipulation means substantially horizontally supports the second substrate above the first substrate and then cancels support of the second substrate.
The above substrate support table and the substrate processing apparatus are suitable to manufacture, e.g. an SOI substrate.
According to the present invention there is provided a substrate processing method of overlaying two substrates and bringing the substrates into contact with each other, characterized by comprising the steps of causing any one of the above substrate support tables to support a first substrate, opposing a second substrate to the first substrate supported by the substrate support table, and overlaying the first substrate and the second substrate and bringing the substrates into contact with each other.
According to the present invention, there is also provided a substrate processing method of overlaying two substrates and bringing the substrates into contact with each other, characterized by comprising the steps of transferring first and second substrates to any one of the above substrate processing apparatuses, overlaying the first and second substrates and bringing the substrates into contact with each other by the substrate processing apparatus, and receiving the substrates in contact with each other from the substrate processing apparatus.
According to the present invention, there is also provided a method of manufacturing an SOI substrate, characterized by comprising the steps of preparing first and second substrates, bringing the first and second substrates into contact with each other by any one of the above substrate processing methods to prepare a substrate having a layer in which a single-crystalline Si layer and an insulating layer are stacked, and separating the substrates which are in contact with each other at a portion other than a contact interface to prepare one of the separated substrates as the substrate having the single-crystalline Si layer on the insulating layer.
According to the present invention, there is also provided a cleaning method characterized by comprising cleaning the substrate support table while accommodating the above substrate support table in a wafer cassette for storing a wafer for manufacturing a semiconductor device.
According to the present invention, there is also provided a method of handling the wafer processing apparatus, characterized by comprising the steps of detaching the substrate support table from the wafer processing apparatus, cleaning the substrate support table while accommodating the detached substrate support table in a wafer cassette for storing a wafer for manufacturing a semiconductor device, and attaching the cleaned substrate support table in the wafer processing apparatus.
According to the present invention, there is also provided a method of manufacturing a substrate support table, characterized by comprising the steps of forming an SiO2 film to cover an entire silicon wafer, forming a first photoresist film on one surface of the SiO2 film, patterning the first photoresist film to expose the SiO2 film at a portion where sealing portions for vacuum chucking are to be formed, etching the SiO2 film at the exposed portion to expose the silicon wafer, removing the remaining first photoresist film, etching the silicon wafer at the exposed portion to a predetermined depth, forming an SiO2 film to cover the entire silicon wafer, forming a second photoresist film on the other surface of the SiO2 film, patterning the second photoresist film to expose the SiO2 film at a portion where a suction hole for vacuum chucking is to be formed, etching the SiO2 film at the exposed portion to expose the silicon wafer, removing the remaining second photoresist film, etching the silicon wafer at the exposed portion to form the suction hole extending through the silicon wafer, and removing the remaining SiO2 film.
According to the present invention, there is also provided a method of manufacturing a substrate support table, characterized by comprising the steps of forming a first film to cover an entire silicon wafer, forming a first photoresist film on one surface of the first film, patterning the first photoresist film to expose the first film at a portion where sealing portions for vacuum chucking are to be formed, etching the first film at the exposed portion to expose the silicon wafer, removing the remaining first photoresist film, etching the silicon wafer at the exposed portion to a predetermined depth, forming a second film to cover the entire silicon wafer, forming a second photoresist film on the other surface of the second film, patterning the second photoresist film to expose the second film at a portion where a suction hole for vacuum chucking is to be formed, etching the second film at the exposed portion to expose the silicon wafer, removing the remaining second photoresist film, etching the silicon wafer at the exposed portion to form the suction hole extending through the silicon wafer, and removing the remaining second film.
Further object, features and advantages of the present invention will become apparent from the following detailed description of embodiments of the present invention with reference to the accompanying drawings.